Tungsten filament and telephone: what they have in common

1. Step 1. Tungsten filament — is part of — Incandescent light bulb. A tungsten coil heated by current.
2. Step 2. Incandescent light bulb — is part of — Torch (flashlight). A bulb (today an LED).
3. Step 3. Torch (flashlight) — has part — Dry cell. Batteries.
4. Step 4. Dry cell — is part of — Transistor radio. Batteries.
5. Step 5. Transistor radio — has part — Loudspeaker. A loudspeaker.
6. Step 6. Loudspeaker — is part of — Telephone. The earpiece reproduces the other person’s voice.

Open Evothings